The Beginning of Chemistry

Oliver J. Thatcher

As astrology was the forerunner of astronomy, so the herald of chemistry was alchemy. In ancient times alchemy went hand in hand with astrology in studying the hidden influences had by the spirits of the heavens and earth over mortals.

Alchemists believed all things to live, and the gases they had learned to drive out of such compounds as red oxide of mercury to be the spirits—the living souls—of these substances. They had not learned to put the wide gulf which we do between life and matter, the spiritual and the material, the supernatural and the natural, but thought all things living, spiritual, and natural. "Everything, even heaven and hell, are of this earth," says the pseudo-Plato. Hence alchemy puzzled itself over the transmutation of metals, the philosopher’s stone, the influence of the spirits of things over health, the elixir of life and the like. Yet most of the best known doctors of the Middle Ages, such as Geber, Avicenna, Aviceborn and Roger Bacon, were alchemists, and the first great representative of medicine in modern times, Paracelsus, was another. It was Paracelsus (1493–1541) who gave alchemy its most useful bent,—"the true use of chemie," says he, "is not to make gold, but medicines."

The Arabians had discovered some of the acids. Paracelsus found the medicinal use of antimony. Glauber (16041–1668) first made artificially sulphate of sodium, called Glauber’s salt, and describes other sulphates and chlorides. He thought mercury and salt to be the principles of all things.

Robert Boyle (1627–1691) examined the influence of pressure on air and developed his law that (the temperature remaining the same) the volume of air (or gas) varies inversely as the pressure. By this time the idea that the gases in things are living souls was pretty well overthrown.

Stahl (1660–1734) advanced the idea that all combustion is the driving off of a fire-element, phlogiston. This theory accounted for many facts and was not refuted for a century. He admitted water, acid, earth and phlogiston as elements.

Robert Hooke in 1665 had set forward the opinion that air contains a substance such as in saltpetre. Mayow (1645–1679), as stated elsewhere, experimented on common air, and separated the "breathing or fire-air" from the rest.

Joseph Black in the latter part of the eighteenth century showed that magnesia and lime weigh less after being heated than before, and that this is because of the expulsion from them of a "fixed air" (carbon dioxide). He found, too, that they would absorb a large amount of heat which became insensible to the touch. This heat he called "latent."

His experiments bring us directly to the work of Priestley, Cavendish and Lavoisier, and the beginning of scientific chemistry.